China Invention Patent No. ZL200510100647.1, applied on Oct. 28, 2005, discloses a full steam-driven internal-combustion engine including a combustion system and a mechanical power system. The mechanical power system includes a turbine wheel and a turbine shaft. The combustion system mainly includes left/right main cylinders and two auxiliary devices, and the auxiliary devices are composed of left/right auxiliary cylinders, huge springs, high-strength levers and high-pressure gas pipes, respectively. The left main cylinder is communicated with the right auxiliary cylinder via the high-pressure gas pipe, and the right main cylinder is communicated with the left auxiliary cylinder via the high-pressure gas pipe. The main cylinder includes a housing and a high-pressure nozzle, wherein the high-pressure nozzle disposed beside the top portion of the housing is communicated with the turbine wheel of the mechanical power system. A coordination card is utilized to connect the top end of the piston of the cylinder to the high-strength lever, and the high-strength lever is connected to the huge spring. The huge spring is fixed by a steel frame, and the high-strength lever is further connected to the piston of the auxiliary cylinder. This full steam-driven internal-combustion engine includes the internal-combustion engine utilized for performing combustion and the gas turbine utilized for producing mechanical power, thereby obtaining high combustion efficiency and reliability, simple structural configuration and operation, low manufacturing cost, and convenience for maintenance. However, the coordination cards connected between the piston of the cylinder and the lever is unstable, the oversized huge springs tend to be deteriorated from fatigue and aging, the positions of the huge springs cause the overlength of the high-pressure nozzles, and no gas supply system is provided. Therefore, this full steam-driven internal-combustion engine is unsuitable for being utilized in large-scale production and different applications.